The present invention relates to an apparatus for treating exhaust particulates resulting from combustion in a diesel engine.
Various types of apparatus for treating exhaust particulates in a diesel engine have been previously proposed. One of such known apparatus is shown in FIGS. 14 and 15 (refer to S. A. E. paper 850015).
As shown in FIG. 14, a turbine rotor of an exhaust turbo supercharger 2 is installed within an exhaust passage 1. For collecting exhaust particulates in exhaust gas, a trap 3 coated with catalyser is installed within the exhaust passage upstream of the turbine rotor. As shown in FIG. 15, the trap 3 includes passages 3B which extend approximately in parallel to an exhaust gas flow and are defined between porous members constructed to form a honeycomb shaped grid 3A. The passages 3B have inlets or outlets sealed by a seal members 3C as shown in FIG. 15.
The exhaust particulates which are collected on the trap 3 are afterburned when an exhaust gas temperature exceeds a range from 350.degree. C. to 400.degree. C. owing to the catalytic action.
A problem encountered in such known apparatus is that, since continuous low speed with low load operation results in insufficient increase in the exhaust gas temperature, the exhaust particulates collected on the trap 3 cannot be afterburned, causing an occurrence of a clogging of the trap 3 due to accumulation of the exhaust particulates. to accumulation of the exhaust particulates.
Another problem encountered is that, when the exhaust gas temperature increases to cause simultaneous afterburning of a large amount of the accumulated exhaust particulates, a temperature of the trap 3 increases to such a degree as to cause the trap 3 to melt down and become deteriorated.